1. Field of the invention
This invention relates to a light-sensitive material comprising a light-sensitive layer containing silver halide, a reducing agent and a polymerizable compound provided on a support and an image-forming methods employing the same.
2. Description of prior arts
Light-sensitive materials comprising a light-sensitive layer containing silver halide, a reducing agent and a polymerizable compound provided on a support can be used in an image forming method in which a latent image of silver halide is formed, and then the polymerizable compound is polymerized to form the corresponding image.
Examples of said image forming methods are described in Japanese Patent Publication Nos. 45(1970)-11149 (corresponding to U.S. Pat. No. 3,697,275), 47(1972)-20741 (corresponding to U.S. Pat. No. 3,687,667) and 49(1974) -10697, and Japanese Patent Provisional Publication Nos. 57(1982)-138632, 57(1982)-142638, 57(1982)-176033, 57(1982)-211146 (corresponding to U.S. Pat. No. 4,557,997), 58(1983)-107529 (corresponding to U.S. Pat. No. 4,560,637), 58(1983)-121031 (corresponding to U.S. Pat. No. 4,547,450) and 58(1983)-169143. In these image forming methods, when the exposed silver halide is developed using a developing solution, the polymerizable compound is induced to polymerize in the presence of a reducing agent (which is oxidized) to form a polymer image. Thus, these methods need a wet development process employing a developing solution. Therefore, the process takes a relatively long time for the operation.
An improved image forming method employing a dry process is described in Japanese Patent Provisional Publication Nos. 61(1986)-69062 and 61(1986)-73145 (the contents of both publications are described in U.S. Pat. No. 4,629,676 and European Patent Provisional Publication No. 0174634A2). In this image forming method, a recording material (i.e., light-sensitive material) comprising a light-sensitive layer containing a light-sensitive silver salt (i.e., silver halide), a reducing agent, a cross-linkable compound (i.e., polymerizable compound) and a binder provided on a support is imagewise exposed to form a latent image, and then the material is heated to polymerize within the area where the latent image of the silver halide has been formed. The above method employing the dry process and the light-sensitive material employable for such method are also described in Japanese Patent Provisional Publication Nos. 61(1986)-183640, 61(1986)-188535 and 61(1986)-228441.
The above-mentioned image forming methods are based on the principle in which the polymerizable compound is polymerized within the area where a latent image of the silver halide has been formed.
Japanese Patent Provisional Publication No. 61(1986)-260241 describes another image forming method in which the polymerizable compound within the area where a latent image of the silver halide has not been formed is polymerized. In the method, when the material is heated, the reducing agent functions as polymerization inhibitor within the area where a latent image of the silver halide has been formed, and the polymerizable compound within the other area is polymerized.
Further, Japanese Patent Provisional Publication No. 61(1986)-73145 (corresponding to European Patent Provisional Publication No. 0174634A2) describes an embodiment of the image-forming methods which comprises: imagewise exposing a light-sensitive material comprising a light-sensitive layer provided on a support wherein the light-sensitive layer contains silver halide, a reducing agent and a polymerizable compound; simultaneously or thereafter developing the light-sensitive material; and pressing the light-sensitive material on an image-receiving material to transfer the unpolymerized polymerizable compound to the image-receiving material.
As the support of the light-sensitive material, a porous sheet is frequently employed, because the porous sheet is light-weight and it is easy to form the light-sensitive layer on the porous sheet. In the case that the unpolymerized polymerizable compound is transferred from the light-sensitive material employing the porous support to the image-receiving material under certain conditions, low density spots of diameter of about 10 .mu.m to about 1 mm containing an extremely small amount of the unpolymerized polymerizable compound are sometimes formed on the image-receiving material within the area where the polymerizable compound should be placed.
The above spot can be minimized by employing a thick sheet as the support, but the thick light-sensitive material is not preferred in consideration of handling in the image formation, space required for the storage of the material and the cost for preparation thereof. Alternatively, the above spot can be also minimized when the image is transferred under high pressure, but it brings about requirement that the pressure device should be more powerful than the conventional one to obtain such high pressure.